The effects of powerline potentials upon spinal cord and electrophysiologic changes in muscle nerve for stimulation and use of the somatosensory evoked potential technique is being conducted. Electrical contact is made between the lower and upper limbs of hogs using commercial type aluminum steel reinforced conductors, copper stranded conductors or stainless steel discs. Potentials from 10 to 14,400 volts are applied. Tissue destruction routinely occurs above 80 volts however the current is limited following tissue charring. Voltages from 10 to 14,400 volts demonstrate currents up to 70 amperes with a resistance of approximately 200 ohms in the hog. Currently reduction was observed at voltages up to 1,000 volts following arcing and skin necrosis. However this reduction was not observed at the higher voltages nor was it observed with application of saline to the tissue. Tissue resistance with stainless steel discs, ellipsoidal electrodes and annular electrodes was proportional to circumference of each. For currents between the hindlimb of the hog the current density was greatest in the artery and nerve followed by muscle fat, bone marrow and bone cortex. Temperature increases in each of the tissues follow the approximate current densities. Preliminary studies demonstrate that temperature damaging to muscle nerve occurred at approximately 50 to 60 degrees C. Electrophysiological techniques are being used to study the effects of powerline potentials upon spinal cord and peripheral nerves.